1. Technical Field
The present invention relates to a liquid ejecting apparatus.
2. Related Art
As a liquid ejecting apparatus, an ink jet printer (hereinafter, referred to as printer) which ejects ink (liquid) onto a recording medium from ejection orifices (nozzles) of a recording head (liquid ejecting head) has been known.
The printer includes a tank which accommodates ink. In the printer, ink in the tank is supplied to a recording head and ink is discharged from the recording head. The ink is commonly made of a dispersion containing solid content such as pigment and a dispersion medium such as a solvent.
When such ink is used in the printer, particularly if the printer is made to be in an OFF state and is kept to be in a non-used state for a long period of time, the solid content in the ink accommodated in the tank is separated and settled down (precipitated). This causes non-uniformity of solid content concentration in the ink. Then, if the solid content is settled down and the solid content concentration is made non-uniform as described above, the following disadvantages are caused. When after power is turned OFF, the power is turned ON again and ink is discharged so as to perform printing, the solid content settled down in the tank is supplied to the ink jet head as it is. Therefore, there arise disadvantages that nozzle clogging of the recording head is caused and further unevenness of recording quality is caused.
Then, the following recording apparatus (printer) has been known (for example, see JP-A-2008-213281) in order to prevent such disadvantages. In the recording apparatus, a main tank and a sub tank are prepared as tanks for storing (accommodating) ink. Further, the main tank and the sub tank are connected with one flow path and one of the main tank and the sub tank is set to be at high pressure and the other is set to be at low pressure. Then, ink is made to reciprocate between the tanks so as to prevent solid content from being settled down in both of the main tank and the sub tank.
In the recording apparatus, capacities of the main tank and the sub tank are set to be substantially the same. Further, in order to completely mix ink for preventing solid content from being settled down in each of the main tank and the sub tank and, ink is fed to one of the main tank and the sub tank until ink in the other becomes substantially empty. Then, a liquid feeding direction is changed before the tank becomes completely empty so as to make ink flow all the time.
However, in the above recording apparatus, operations while the power is in the ON state are described but operations while the power is in the OFF state are not described at all. Therefore, operations when the power is switched to the ON state from the OFF state are not considered at all.
For example, it is assumed that the capacities of the main tank and the sub tank are set to 100 ml and power is turned OFF while ink is being fed from the main tank to the sub tank. Further, it is assumed that a residual amount of ink in the main tank is 90 ml and a residual amount of ink in the sub tank is 10 ml when the power is turned OFF. In this case, even if solid contents of inks in both of the tanks have been settled down while the power has been in the OFF state, if ink is flown into the sub tank from the main tank by 10 ml when the power is turned ON, ink in the sub tank is sufficiently stirred.
However, if it is assumed that the residual amount of ink in the main tank is 10 ml and the residual amount of ink in the sub tank is 90 ml, even if ink is flown into the sub tank from the main tank by 10 ml when the power is turned ON, a sufficient stirring effect cannot be obtained in the sub tank.